OpenLayers 3 API Documentation - Class: ol.Collection

new Collection

Stability: experimental

A mutable MVC Array.

Parameters:

Name	Type	Argument	Description
`array`	Array	<optional>	Array.

Source:

collection.js, line 64

Extends

ol.Object

Observable Properties

Name	Type	Settable	Event	Description
`length`	number	no	`change:length`	the length of the array

Methods

bindTo Stability: experimental

The bindTo method allows you to set up a two-way binding between a source and target object. The method returns an ol.ObjectAccessor with a transform method that lets you transform values on the way from the source to the target and on the way back.

For example, if you had two map views (sourceView and targetView) and you wanted the target view to have double the resolution of the source view, you could transform the resolution on the way to and from the target with the following:

sourceView.bindTo('resolution', targetView)
  .transform(
    function(sourceResolution) {
      // from sourceView.resolution to targetView.resolution
      return 2 * sourceResolution;
    },
    function(targetResolution) {
      // from targetView.resolution to sourceView.resolution
      return targetResolution / 2;
    }
  );

Parameters:

Name	Type	Argument	Description
`key`	string		Key name.
`target`	ol.Object		Target.
`targetKey`	string	<optional>	Target key.

Inherited From:

ol.Object#bindTo

Source:

object.js, line 232

Returns:

Type: ol.ObjectAccessor

clear Stability: experimental

Remove all elements from the collection.

Source:

collection.js, line 84

dispatchChangeEvent Stability: experimental

Inherited From:

ol.Observable#dispatchChangeEvent

Source:

observable.js, line 35

extend Stability: experimental

Parameters:

Name	Type	Description
`arr`	Array	Array.

Source:

collection.js, line 96

Returns:

This collection.

Type: ol.Collection

forEach Stability: experimental

Iterate over each element, calling the provided callback.

Parameters:

Name	Type	Argument	Description
`f`	function		The function to call for every element. This function takes 3 arguments (the element, the index and the array). The return value is ignored.
`this`	S	<optional>	The object to use as `this` in `f`.

Source:

collection.js, line 114

get Stability: experimental

Gets a value.

Parameters:

Name	Type	Description
`key`	string	Key name.

Inherited From:

ol.Object#get

Source:

object.js, line 289

Returns:

Value.

Type: *

getArray Stability: experimental

Get a reference to the underlying Array object. Warning: if the array is mutated, no events will be dispatched by the collection, and the collection's "length" property won't be in sync with the actual length of the array.

Source:

collection.js, line 127

Returns:

Array.

Type: Array

getAt Stability: experimental

Get the element at the provided index.

Parameters:

Name	Type	Description
`index`	number	Index.

Source:

collection.js, line 138

Returns:

Element.

Type: *

getLength Stability: experimental

Get the length of this collection.

Source:

collection.js, line 148

Returns:

Length.

Type: number

getProperties Stability: experimental

Get an object of all property names and values.

Inherited From:

ol.Object#getProperties

Source:

object.js, line 348

Returns:

Object.

Type: Object.<string, *>

insertAt Stability: experimental

Insert an element at the provided index.

Parameters:

Name	Type	Description
`index`	number	Index.
`elem`	*	Element.

Source:

collection.js, line 159

notify Stability: experimental

Notify all observers of a change on this property. This notifies both objects that are bound to the object's property as well as the object that it is bound to.

Parameters:

Name	Type	Description
`key`	string	Key name.

Inherited From:

ol.Object#notify

Source:

object.js, line 368

on Stability: experimental

Listen for a certain type of event.

Parameters:

Name	Type	Argument	Description
`type`	string \| Array.<string>		The event type or array of event types.
`listener`	function		The listener function.
`this`	Object	<optional>	The object to use as `this` in `listener`.

Inherited From:

ol.Observable#on

Source:

observable.js, line 58

Returns:

Unique key for the listener.

Type: goog.events.Key

once Stability: experimental

Listen once for a certain type of event.

Parameters:

Name	Type	Argument	Description
`type`	string \| Array.<string>		The event type or array of event types.
`listener`	function		The listener function.
`this`	Object	<optional>	The object to use as `this` in `listener`.

Inherited From:

ol.Observable#once

Source:

observable.js, line 71

Returns:

Unique key for the listener.

Type: goog.events.Key

pop Stability: experimental

Remove the last element of the collection.

Source:

collection.js, line 172

Returns:

Element.

Type: *

push Stability: experimental

Insert the provided element at the end of the collection.

Parameters:

Name	Type	Description
`elem`	*	Element.

Source:

collection.js, line 183

Returns:

Length.

Type: number

remove Stability: experimental

Removes the first occurence of elem from the collection.

Parameters:

Name	Type	Description
`elem`	*	Element.

Source:

collection.js, line 196

Returns:

The removed element or undefined if elem was not found.

Type: *

removeAt Stability: experimental

Remove the element at the provided index.

Parameters:

Name	Type	Description
`index`	number	Index.

Source:

collection.js, line 214

Returns:

Value.

Type: *

set Stability: experimental

Sets a value.

Parameters:

Name	Type	Description
`key`	string	Key name.
`value`	*	Value.

Inherited From:

ol.Object#set

Source:

object.js, line 399

setAt Stability: experimental

Set the element at the provided index.

Parameters:

Name	Type	Description
`index`	number	Index.
`elem`	*	Element.

Source:

collection.js, line 230

setValues Stability: experimental

Sets a collection of key-value pairs.

Parameters:

Name	Type	Description
`values`	Object.<string, *>	Values.

Inherited From:

ol.Object#setValues

Source:

object.js, line 428

un Stability: experimental

Unlisten for a certain type of event.

Parameters:

Name	Type	Argument	Description
`type`	string \| Array.<string>		The event type or array of event types.
`listener`	function		The listener function.
`this`	Object	<optional>	The object to use as `this` in `listener`.